Ubuntu – Apache server doesn’t start automatically

I installed Apache a long time a go as part of setting up the development environment on my laptop.

However, since I stopped it some months back, it no longer starts automatically on boot. I have this problem on my laptop at home AND on my laptop at work.

I both cases, I installed Apache in Ubuntu 10.10 some months ago, used it for several weeks without a glitch, but then one day I stopped it and now it no longer starts automatically. I tried running the update rc for it manually, but was told the init script is already in use.

However, starting/restarting it manually with

sudo service apache2 start/restart

works fine. In both cases, I let it be until after the upgrade to 11.04, because I hoped it would be solved by the new version. But it's not! I'd be grateful if someone can tell me how to have Apache start automatically once more.